
©Silberschatz, Korth and Sudarshan3.57Database System Concepts, 5th Edition, Oct 5, 2006
Updates Through Views (Cont.)
Updates Through Views (Cont.)
Some updates through views are impossible to translate into
updates on the database relations
zcreate view v as
select loan_number, branch_name, amount
from loan
where branch_name = ‘Perryridge’
insert into vvalues ('L-99','Downtown', '23')
Others cannot be translated uniquely
zinsert into all_customer values ('Perryridge', 'John')
Have to choose loan or account, and
create a new loan/account number!
Most SQL implementations allow updates only on simple views
(without aggregates) defined on a single relation